Loud-speaker



7 June 11, 1929. w G, A E 1.716.772

LOUD SPEAKER Filed Aug. 26, 1927 2 Sheets-Sheet l z 4 9 K L f 'M lawn 10 2 7 2/ M/VE N TOR 3G. GALE lime 11, 1929. v w E 1,716,772

LOUD SPEAKER Filed Aug. 26, 1927 2 Sheets-Sheet 2 1' 7 /NVENTOR l0 6% I \2 mam ATTORNEYS Patented June 11, 1929.

UNITEDSTATES ATENT OFFICE.

WALTER enonen GALE, on .cAvEasirAM, NEAR "REA Ins, ENGLAND, AssrerioR T0 REGINALD IVESON nEnHAi/L'on Lennon, ENeLAivn LOUD-SPEAKER.

Application filed August zeg sz'c, Serial No. 215,543, as a Great liritain august sqg'isas.

This invention relates to improvements in the construction of loud speaking telephone devices'known-asloudspeakeraas used in the reception of radio telegrapliyand telephony. The inventionis particularly applicable to loud speakers of the type having'the usual resilient armature and 'electro-magnetic system coupled with a diaphragm which if of conical shape, as is frequently the case, is tached to the a-rmatu-reat its apex.

Such conical (liaphragmsusually consist of a compound'cone built up of two or more cones of any suitablematerial as pap'er parclr merit, metal foil, thin wood and thelike in such a manner that the apices of the several cones are on a comnion axis the bases being in acoinmon plane and the ci-rcu-mferenccsof the cones being securedtogether, the whole forming ashell or bracedstructure, or they consist of spiralgor concentric hoops or hands interwoven with radial-ribs the framework thus formed being covered: with thin paper, parchment, oiled'silk-or the like. I

- The periphery thecone diaphragm has been :clanipedin supporting fr'ames'or rings or the cone has been supported at the apex only,-the conical surface being self-supporting by reason of't he frameworkor bracing of the diaphragm. 7 i It has however beenfound that the use of such frameworl-rtendsto cause distortion due to parasitic vibrations in the frame while the various shell type cones tend to overdevelop certain frequencies in the musical register and power losses occur due I believe to the inertia of the diaphragm, and an apparent time lag .as between the apex and the base of th cone resulting in loss of volume.

Moreover it is evident that a conical diaphragm which is self-supporting without framework and which is also so formed as to reduce to a minimum the time lag of the base of the cone relative to the apex will amplify efliciently and accurately.

According to this invention the conical diaphragm of a loud speaker is supported by a number of resilient or flexible fingers or strips formed by making parallel or divergent cuts in the thickness of the plane surface or wall of the cabinet, so that the said fingers or strips are integral with such plane surface or wall and are coupled at or near their free ends to the base or periphery of the diaphragm,

The eferesaid plane may the p or both.

It will be obvious that the flexible strips surface or frame employed to support. the electro magnetic systeni' such the inner'or outerwall of alc abinetror box or any Wall plaque or frame andthe diaphragm consists of a hollow cone of paper, anetal foil, "thin wood, silkor the likeior'a OOIfibiIlittiOIlsOf the like materials attached .in :the usual manner at a point :at .ornear the apexof the cone to the vibratory body, the periphery of the cone resting on the plane surface which isso cut or formed or built as to have a num 3 berof the resilient strips on which the pe .iplacedtoform outwardly radiating linqgers extending from .a point .atsor nearthe centre of the base of theIcone to theperiphery I of the cone. a v 1 p The circumference of thefcone may, be strengthened by pleating or folding and the periphery of the cone may be attached to the flexible fingers by; any suitable means. In this manner the cone is suspended between the armature and the .fiexible strips and has no framework in contact with the conical, *surfaceand the flexibility of the said fingers diminishes the; effect of time lag previously referred to. In order that the periphery of the cone may not be in direct contact with the plane surface or the flexible fingers, which tends to cause distortion of the reproduced sounds a rim or band of felt, cloth, rubber or the like may be fixedtothe periphery of the 1 cone or to the plane surface where contact with the cone is made or the periphery of the cone may be coated with hair orflock,

' by means of an adhesive, or felt or other material insmall pieces may be attached to the periphery of the cone or to the plane surface may be arranged in an ornamental design and that they may be formed in any manner other than radially extended from the centre.

A method of carrying out the invention is illustrated in the accompanying drawings wherein a Figure 1 is a plan of the member hereinbefore referred to as the plane surface seen the underside of Figure 2.

iiigurc elevation of an apparatus Referring to the drawings it will be seen that the saw cuts 10, in the thickness of the plane surface 7, are so arranged as to form flexible fingers 2, and a method of combining the fingers so formed and the sound apertures 8 into an ornamental design is indicated in Figure 1. Y

The cone 1 is attached to the sound post 5 at or near to the apex by suitable means, cone washers 11 and clamping nuts 12 being preferred as shewn in Figures 2 and 4 and the sound post 5 is attached in any appropriate manner to the armature or other Vibratory body.

The circumference of the cone may be strengthened by means of a rib or fold 9 in order to assist in maintaining circular shape.

The electro-magnetic system 3 may be housed between the plaque or member 7 and the cone 1 but may be also situated opposite the apex of the cone and outside the cone and where the electromagnetic system is housed as shown in the drawings the adjust ment means 6 may protrude. v

Damping spacers of felt, wool or hair or thelike 4 may be placed between the cone 1 and the fingers 2, or the periphery'of the cone may be coated with flock or rest on a felt or the like band, or the dampingspacers 4 may be placed at intervals round the edge of thze cone or on the plane surface or member The cone may be attached to the members 2 at any point but is preferably secured at the In Figures 2 and 1 the fingers areshown raised above the plane of the member 7 by reason of initial tension applied to the cone before securing the apex to the sound post 5 by means of nut-s 12 but this is not essential to the eflicient operation of the device. What I claim is e e 1. In loud speakers the combination with a plane surface supporting the electro-magnetic system, of a conical diaphragm and a plurality of resilient fingers formed in the said plane surface and coupled by their free ends to the periphery of the diaphragm.

2. In a loud speaker the combination with a conical diaphragm, coupled at its apex to an armature, of a base supporting said armature and a series of flexible fingers integral with said base and coupled by their free ends to the periphery of the diaphragm. I

3. In loud speakers the combination with a plane surface supporting the electro-magnetic system, of a conical diaphragm, a plurality of resilient fingers formed in the said plane surface and coupled by'their free ends to the periphery of the diaphragm, and clamping' means interposed between said diaphragm periphery and said plane surface.

4. In a loud speaker the combination with a conical diaphragm, coupled at its apex to an armature, of a base supporting said armature, a series of flexiblefingers integral with said base and coupled by their free ends to the periphery of the diaphragm, and a series of damping spacers on said base between said free ends and said periphery.

In testimony whereof I affix my signature.

. WALTER- GEORGE GALE. 

